<!DOCTYPE html>
<html>
  <head>
    <meta charset="UTF-8" />
    <title>CSS 太阳系</title>
    <link rel="stylesheet" href="style.css" />
  </head>
  <body>
    <div class="container">
      <div class="sun"></div>
      <div class="earth">
        <div class="moon"></div>
      </div>
    </div>
  </body>
</html>
